public void invalidate() {
invalidate(true);
}
public void invalidate(boolean invalidateCache) {
invalidateInternal(0, 0, mRight - mLeft, mBottom - mTop, invalidateCache, true);
}
void invalidateInternal(int l, int t, int r, int b, boolean invalidateCache,
boolean fullInvalidate) {
if (mGhostView != null) {
mGhostView.invalidate(true);
return;
}
if (skipInvalidate()) {
return;
}
if ((mPrivateFlags & (PFLAG_DRAWN | PFLAG_HAS_BOUNDS)) == (PFLAG_DRAWN | PFLAG_HAS_BOUNDS)
|| (invalidateCache && (mPrivateFlags & PFLAG_DRAWING_CACHE_VALID) == PFLAG_DRAWING_CACHE_VALID)
|| (mPrivateFlags & PFLAG_INVALIDATED) != PFLAG_INVALIDATED
|| (fullInvalidate && isOpaque() != mLastIsOpaque)) {
if (fullInvalidate) {
mLastIsOpaque = isOpaque();
mPrivateFlags &= ~PFLAG_DRAWN;
}
mPrivateFlags |= PFLAG_DIRTY;
if (invalidateCache) {
mPrivateFlags |= PFLAG_INVALIDATED;
mPrivateFlags &= ~PFLAG_DRAWING_CACHE_VALID;
}
//这个地方是重点逻辑，主要分析这个
// Propagate the damage rectangle to the parent view.
final AttachInfo ai = mAttachInfo;
final ViewParent p = mParent;
if (p != null && ai != null && l < r && t < b) {
final Rect damage = ai.mTmpInvalRect;
damage.set(l, t, r, b);
p.invalidateChild(this, damage);
}
// Damage the entire projection receiver, if necessary.
if (mBackground != null && mBackground.isProjected()) {
final View receiver = getProjectionReceiver();
if (receiver != null) {
receiver.damageInParent();
}
}
}
}
@UiThread
public abstract class ViewGroup extends View implements ViewParent, ViewManager {
@Override
public final void invalidateChild(View child, final Rect dirty) {
ViewParent parent = this;
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
//这是一个从当前的布局View向上不断遍历当前布局View的父布局，最后遍历到ViewRootImpl的循环
do {
View view = null;
if (parent instanceof View) {
view = (View) parent;
}
//这里调用的是父布局的invalidateChildInParent方法
parent = parent.invalidateChildInParent(location, dirty);
} while (parent != null);
}
}
@Override
public ViewParent invalidateChildInParent(final int[] location, final Rect dirty) {
if ((mPrivateFlags & PFLAG_DRAWN) == PFLAG_DRAWN ||
(mPrivateFlags & PFLAG_DRAWING_CACHE_VALID) == PFLAG_DRAWING_CACHE_VALID) {
if ((mGroupFlags & (FLAG_OPTIMIZE_INVALIDATE | FLAG_ANIMATION_DONE)) !=
FLAG_OPTIMIZE_INVALIDATE) {
...
//这里也是一些计算绘制区域的内容
return mParent;
} else {
mPrivateFlags &= ~PFLAG_DRAWN & ~PFLAG_DRAWING_CACHE_VALID;
//这里也是一些计算绘制区域的内容
return mParent;
}
}
return null;
}
}
public final class ViewRootImpl implements ViewParent,View.AttachInfo.Callbacks, ThreadedRenderer.HardwareDrawCallbacks {
//如果View没有父布局，那invalidateInternal方法就会调用这个方法
@Override
public void invalidateChild(View child, Rect dirty) {
invalidateChildInParent(null, dirty);
}
//ViewGroup的invalidateChild方法最后会调用到这里
@Override
public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
checkThread();
//如果dirty为null就表示要重绘当前ViewRootImpl指示的整个区域
if (dirty == null) {
invalidate();
return null;
//如果dirty为empty则表示经过计算需要重绘的区域不需要绘制
} else if (dirty.isEmpty() && !mIsAnimating) {
return null;
}
return null;
}
private void invalidateRectOnScreen(Rect dirty) {
final Rect localDirty = mDirty;
...
if (!mWillDrawSoon && (intersected || mIsAnimating)) {
//调用scheduleTraversals方法进行绘制
scheduleTraversals();
}
}
//绘制整个ViewRootImpl区域
void invalidate() {
mDirty.set(0, 0, mWidth, mHeight);
if (!mWillDrawSoon) {
//调用scheduleTraversals方法进行绘制
scheduleTraversals();
}
}
}
void scheduleTraversals() {
if (!mTraversalScheduled) {
mTraversalScheduled = true;
mTraversalBarrier = mHandler.getLooper().getQueue().postSyncBarrier();
mChoreographer.postCallback(
Choreographer.CALLBACK_TRAVERSAL, mTraversalRunnable, null);
if (!mUnbufferedInputDispatch) {
scheduleConsumeBatchedInput();
}
notifyRendererOfFramePending();
pokeDrawLockIfNeeded();
}
}
final class TraversalRunnable implements Runnable {
@Override
public void run() {
doTraversal();
}
}
final TraversalRunnable mTraversalRunnable = new TraversalRunnable();
void doTraversal() {
if (mTraversalScheduled) {
mTraversalScheduled = false;
mHandler.getLooper().getQueue().removeSyncBarrier(mTraversalBarrier);
if (mProfile) {
Debug.startMethodTracing("ViewAncestor");
}
performTraversals();
if (mProfile) {
Debug.stopMethodTracing();
mProfile = false;
}
}
}
@UiThread
public class View implements Drawable.Callback, KeyEvent.Callback,AccessibilityEventSource {
...
public void postInvalidate() {
postInvalidateDelayed(0);
}
public void postInvalidate(int left, int top, int right, int bottom) {
postInvalidateDelayed(0, left, top, right, bottom);
}
public void postInvalidateDelayed(long delayMilliseconds) {
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
attachInfo.mViewRootImpl.dispatchInvalidateDelayed(this, delayMilliseconds);
}
}
...
}
//发送消息
//更多内容：https://github.com/yangchong211
public void dispatchInvalidateDelayed(View view, long delayMilliseconds) {
Message msg = mHandler.obtainMessage(MSG_INVALIDATE, view);
mHandler.sendMessageDelayed(msg, delayMilliseconds);
}
//接收消息
final class ViewRootHandler extends Handler {
@Override
public String getMessageName(Message message) {
switch (message.what) {
case MSG_INVALIDATE:
return "MSG_INVALIDATE";
}
return super.getMessageName(message);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_INVALIDATE:
((View) msg.obj).invalidate();
break;
}
}
}
//View.class
@CallSuper
public void requestLayout() {
if (mMeasureCache != null) mMeasureCache.clear();
if (mAttachInfo != null && mAttachInfo.mViewRequestingLayout == null) {
// Only trigger request-during-layout logic if this is the view requesting it,
// not the views in its parent hierarchy
ViewRootImpl viewRoot = getViewRootImpl();
if (viewRoot != null && viewRoot.isInLayout()) {
if (!viewRoot.requestLayoutDuringLayout(this)) {
return;
}
}
mAttachInfo.mViewRequestingLayout = this;
}
//设置PFLAG_FORCE_LAYOUT标记位，这样就会导致重新测量和布局
mPrivateFlags |= PFLAG_FORCE_LAYOUT;
//设置PFLAG_INVALIDATED就会进行重新绘制
mPrivateFlags |= PFLAG_INVALIDATED;
if (mParent != null && !mParent.isLayoutRequested()) {
//不断调用上层View的requestLayout方法
mParent.requestLayout();
}
if (mAttachInfo != null && mAttachInfo.mViewRequestingLayout == this) {
mAttachInfo.mViewRequestingLayout = null;
}
}
@Override
public void requestLayout() {
if (!mHandlingLayoutInLayoutRequest) {
checkThread();
mLayoutRequested = true;
scheduleTraversals();
}
}
public final void measure(int widthMeasureSpec, int heightMeasureSpec) {
final boolean forceLayout = (mPrivateFlags & PFLAG_FORCE_LAYOUT) == PFLAG_FORCE_LAYOUT;
if (forceLayout || needsLayout) {
// first clears the measured dimension flag
mPrivateFlags &= ~PFLAG_MEASURED_DIMENSION_SET;
int cacheIndex = forceLayout ? -1 : mMeasureCache.indexOfKey(key);
if (cacheIndex < 0 || sIgnoreMeasureCache) {
//调用onMeasure方法
onMeasure(widthMeasureSpec, heightMeasureSpec);
mPrivateFlags3 &= ~PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT;
} else {
long value = mMeasureCache.valueAt(cacheIndex);
setMeasuredDimensionRaw((int) (value >> 32), (int) value);
mPrivateFlags3 |= PFLAG3_MEASURE_NEEDED_BEFORE_LAYOUT;
}
//设置PFLAG_LAYOUT_REQUIRED标记位，用于layout方法
mPrivateFlags |= PFLAG_LAYOUT_REQUIRED;
}
}
public void layout(int l, int t, int r, int b) {
//由于measure方法中设置了PFLAG_LAYOUT_REQUIRED标记位，所以会进入调用onLayout方法进行布局流程
if (changed || (mPrivateFlags & PFLAG_LAYOUT_REQUIRED) == PFLAG_LAYOUT_REQUIRED) {
onLayout(changed, l, t, r, b);
if (shouldDrawRoundScrollbar()) {
if(mRoundScrollbarRenderer == null) {
mRoundScrollbarRenderer = new RoundScrollbarRenderer(this);
}
} else {
mRoundScrollbarRenderer = null;
}
//取消PFLAG_LAYOUT_REQUIRED标记位
mPrivateFlags &= ~PFLAG_LAYOUT_REQUIRED;
ListenerInfo li = mListenerInfo;
if (li != null && li.mOnLayoutChangeListeners != null) {
ArrayList<OnLayoutChangeListener> listenersCopy =
(ArrayList<OnLayoutChangeListener>)li.mOnLayoutChangeListeners.clone();
int numListeners = listenersCopy.size();
for (int i = 0; i < numListeners; ++i) {
listenersCopy.get(i).onLayoutChange(this, l, t, r, b, oldL, oldT, oldR, oldB);
}
}
}
//取消PFLAG_FORCE_LAYOUT标记位
mPrivateFlags &= ~PFLAG_FORCE_LAYOUT;
mPrivateFlags3 |= PFLAG3_IS_LAID_OUT;
}
View之invalidate，requestLayout，postInvalidate
原文：https://www.cnblogs.com/yc211/p/10582656.html